Colic is a condition some infants suffer from during early months after birth, wherein presence of air in the digestive system is indicated as a major cause. Air ingestion is unavoidable both in breast-feeding and bottle-feeding due to the presence of vacuum in the infant's mouth during feeding. However, it is desired to reduce the amount of air ingested by the infant in order to prevent or alleviate colic-like symptoms.
Different strategies are used to minimize air ingestion during feeding, including reducing the effort required by the infant, for instance by reducing the vacuum through providing a venting valve in the bottle. However, in certain designs, since the venting valve opens under the liquid level for the majority of the feed, air entering into the bottle through the venting valve leads to the formation of bubbles within the liquid.
Presence of bubbles increases the chance of some bubbles being carried into the teat and thus eventually arriving in the mouth of the infant. A large number of small bubbles can provide a high surface to volume ratio which eventually can result in a higher dissolution of air within the milk. In addition, bubbling of air through milk potentially can reduce the nutritive value of milk by oxidation of certain nutrients. Further, the bubbles accumulate on the free surface of the liquid within the feeding bottle creating a foam that can be perceived negatively by some caregivers.
US 2016/02621985 discloses a vented baby bottle and comprises a bottle, a nipple, a mounting ring, and a vent assembly. Aeration (gas bubbles) in the bottle's fluid is decreased by establishing an air passage through the mounting ring into the interior of the bottle. When this air passage is used in combination with a vent assembly having a self closing vent valve, the system allows atmospheric air to vent into the interior of the baby bottle when a lower than atmospheric pressure is created within the bottle, thereby preventing the aeration of the fluid contained in the bottle.